Make the mushroom broth: Bring 4 cups water to a simmer in a medium saucepan, completely submerge the mushrooms, and soak for 25 minutes. Remove the mushrooms with a slotted spoon and slice into 1/2-inch pieces. Strain the water and return it to the saucepan; add the chicken broth, bring to a simmer, and keep warm. Make the risotto: Cook bacon in a large saucepan until crisp. Transfer to a small bowl and set aside; reserve fat. Sauté onions in 2 tablespoons bacon fat until translucent -- about 5 minutes. Add the rice and cook over medium heat until slightly translucent -- about 5 minutes. Add the wine and cook until absorbed. Add 1 cup of hot broth, stirring constantly, and cook until absorbed, continue stirring and adding broth by the cupfuls until risotto is creamy and rice is cooked through but slightly al dente -- about 25 minutes. Stir in the bacon, Parmesan, salt, and pepper and serve immediately or freeze (see Step 3). Freeze the leftover risotto: Shape 1/4 cupfuls of cooled risotto into 2-inch patties and coat with bread crumbs. Stack patties between sheets of waxed paper and transfer to an airtight container. Store frozen for up to 2 months. To serve, cook frozen patties in a lightly oiled or buttered skillet for 6 minutes on each side. Drain on paper towels.